The purpose of such an intake port is to achieve in a selective manner a swirling motion of the cylinder charge in the combustion chamber in certain operating zones of the internal combustion engine and thus assure stable combustion, while during other operating states of the internal combustion engine such a swirling motion is undesirable and should be avoided.
Such an intake port is described in DE 93 19 545 U1. In this intake port the cross-section of the port is subdivided by a wall into two partial channels which combine to form an intake zone directly in front of the intake valve closing the combustion chamber of the internal combustion chamber. The wall forming a partial plane which runs at least in the intake zone transversely to the axis of the cylinder of the internal combustion engine, and the partial channels are provided with a controllable throttle flap.
Such an intake port has the disadvantage that the throttle flap additionally arranged in its partial cross-section even in the open state prevents the unimpeded passage of the gas, especially at high rpm of the internal combustion engine. This leads to undesired turbulence in the flow path and to losses of the degree of filling. Likewise, detached flow on the downstream edge of the wall separating the two partial channels is unavoidable so that losses in the degree of filling are also caused by this.
DE 41 35 271 A1 describes an intake pipe of an internal combustion engine in which, in order to adapt to the oscillating behavior of operation of the internal combustion engine, the cross-section of flow is varied by means of an elastic inflatable expansion body, said expansion body being designed in the form of a ring which concentrically alters the cross-section of flow. An influence on the inflow direction of the gas into the cylinder of the internal combustion engine is impossible according to the technical concept presented here.